[CASSANDRA-6825] Slice Queries Can Skip Intersecting SSTables

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.0.7, 2.1 beta2

Environment

quad core Windows7 x64, single node cluster
Cassandra 2.0.5

• Severity: Normal
• Since Version: 2.0.3
• Assignee: Tom Hobbs
• Reporter: Bill Mitchell

Authors

Tom Hobbs

Reviewers

Sylvain Lebresne

• Created: 07/Mar/14 21:57
• Updated: 16/Apr/19 09:31
• Resolved: 02/Apr/14 20:03

Description

Investigating another problem, I needed to do COUNT on the several partitions of a table immediately after a test case ran, and I discovered that count on the full table and on each of the partitions returned different counts.

In particular case, SELECT COUNT FROM sr LIMIT 1000000; returned the expected count from the test 99999 rows. The composite primary key splits the logical row into six distinct partitions, and when I issue a query asking for the total across all six partitions, the returned result is only 83999. Drilling down, I find that SELECT * from sr WHERE s = 5 AND l = 11 AND partition = 0; returns 30,000 rows, but a SELECT COUNT with the identical WHERE predicate reports only 14,000.

This is failing immediately after running a single small test, such that there are only two SSTables, sr-jb-1 and sr-jb-2. Compaction never needed to run.

In selectrowcounts.txt is a copy of the cqlsh output showing the incorrect count results.

Issue Links

• is duplicated by: CASSANDRA-6826 Query returns different number of results depending on fetchsize